Post-fire recovery of fish populations in Blue River, AZ

Authors: Wade Massure, Brian R. Kesner, Jamie Wisenall, Paul C. Marsh

Year: 2013 (xlv)

Abstract

More than half a million acres in eastern Arizona and western New Mexico were burned in the Wallow Fire of 2011 including portions of the upper Blue River and its tributaries. Ash flows and fish kills were observed throughout the Blue River basin following the wildfire devastation and a monitoring program was initiated to study the post-fire recovery of fish populations. Investigations focused primarily on abundance and distribution of native and non-native fish populations. Blue River and its major tributaries (Campbell Blue and Dry Blue) were sampled in 2011, 2012, and 2013 using backpack electrofishing and seining. Five native species were encountered in all three sample years; desert sucker Pantosteus clarki, Sonora sucker Catostomus insignis, longfin dace Agosia chrysogaster, speckled dace Rhinichthys osculus, and loach minnow Tiaroga cobitis. However, fewer than five fish were encountered in three of eight sites sampled in 2011. In 2012, each of six sites had at least 50 fish including young-of-year Sonora sucker or desert sucker. The native fish catch was similar in 2012 and 2013, but was approximately 2.3 times greater than in 2011. Eleven loach minnow were captured in 2013, the most captured since the fire. Lastly, we would like to note the first reports of non-native green sunfish Lepomis cyanellus for Blue River. This invasive species was not known to occur in the system prior to the Wallow Fire and construction of a fish barrier near the mouth of the stream, but it was independently documented by two groups working both immediately- and well-above the barrier, and below, in 2012. Green sunfish source and mode of access are unknown. Regardless, its establishment in Blue River represents a threat to resident native fishes and to conservation plans that include management of other native species.